Making Sense of the Census: Hollerith’s Punched Card Solution

The 60 million cards punched in the 1890 United States census were fed manually into machines like this for processing. The dials counted the number of cards with holes in a particular position. The sorter on the right would be activated by certain hole combinations, allowing detailed statistics to be generated (for example, the number of married farmers over 40 years of age). An average operator could process about 7,000 cards a day, at least ten times faster than manual methods.

Making Sense of the Census: Hollerith's Punched Card Solution

Nothing stimulates creativity like a good crisis.

The U.S. Constitution requires a census every decade. That was manageable in 1790 with fewer than four million Americans to tally. Not so simple a century later, with 63 million. Estimates warned that the 1890 census wouldn’t be finished before the 1900 census began!

The government’s answer? A contest to devise a solution. Herman Hollerith won. He suggested recording data on punched cards, which would be read by a tabulating machine.

Herman Hollerith’s tabulating system sped up the 1890 census, but there was still a lot of manual work involved. Most holes in each of the 60 million cards were individually punched, and the cards were moved and stacked by hand. A similar process was later used by the Department of Agriculture for farm censuses.

To record data using the pantograph punch, the operators had to carefully align a pin with a hole in a guide plate, and then push hard to create a corresponding round hole in the stiff paper card. It was a slow process compared to the later keyboard-driven punches.